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P0158: O2 Sensor Circuit High Voltage (Bank 2 Sensor 2)

Severity: Low With a steady light and normal running, arrange diagnosis soon. Stop for a flashing light, severe misfire, overheating, or a glowing catalyst; do not assume those symptoms are only a sensor fault.

What does P0158 mean?

Bank 2 sensor 2 reports an oxygen-signal voltage above the expected range. The rear sensor may be detecting rich exhaust, but a signal wire shorted to voltage can produce the same code.

Generic OBD-II definition: O2 Sensor Circuit High Voltage (Bank 2 Sensor 2). Confirm applicability in your vehicle service information.

Common causes

  • Rear sensor signal shorted to power
  • Faulty bank 2 downstream sensor
  • Rich engine operation or exhaust-related mixture error

Symptoms

  • Check engine light
  • Possible loss of economy
  • Rough running if the engine is actually rich

Diagnostic focus

Look for P0175 or bank 2 upstream high-signal codes. Matching front/rear rich indications suggest a different path than a single rear input stuck high with otherwise normal mixture data.

Can I keep driving with P0158?

Severity: Low With a steady light and normal running, arrange diagnosis soon. Stop for a flashing light, severe misfire, overheating, or a glowing catalyst; do not assume those symptoms are only a sensor fault.

If the check engine light is flashing or the car runs badly, stop driving and have it checked.

Typical fixes

  • Inspect the rear harness for contact with hot exhaust
  • Check front-sensor data and rich-fueling codes
  • Verify the rear signal electrically before replacing the sensor

Related codes

P0156
O2 Sensor Circuit Malfunction (Bank 2 Sensor 2)P0157
O2 Sensor Circuit Low Voltage (Bank 2 Sensor 2)P0175
System Too Rich (Bank 2)

Sources & review

Definitions and diagnostic background checked 2026-11-06. Generic guidance, not a substitute for the service procedure for your exact year, engine, and transmission.